London has been battered by 50mph winds that have felled trees and caused travel chaos. Powerful gusts swept across the capital as the Met Office issued a yellow "be aware" weather alert for most of the country.

For Sir Ian Blair, the first indication that something might be awry was that Boris Johnson had combed his hair in advance of what was supposed to be a routine meeting to discuss policing in the capital.

So when Blair walked into the Mayor's office last October, there was an alarming absence of Johnsonian bonhomie or dishevelment.

There were no "how are you, old bean", no studiously self-effacing references to the Commissioner's 35 years' experience, no suggestion in his flattened blond locks and neatly buttoned suit that the Mayor had been pulled backwards through a hedge on his way into City Hall.

"Boris just said: 'There's no easy way of saying this Ian, but I want a change of leadership in the Met.'"

As Boris spoke, he would look to his side at his deputy in charge of policing, Kit Malthouse, as if seeking to stiffen his own backbone.

"Once you hear something like that, there is a moment of what I think is called cognitive dissonance, you just can't quite grasp what has been said, and it was so unexpected."

It took a good 20 seconds for Blair to realise that this man he says he still regards as very "likeable" - which of course is not quite the same as "nice" - was getting rid of him.

"There was a deathly silence, and then Kit said something similar," Blair recalls. "And I just looked at them and I said: 'This is all very interesting but you can't do it, you don't have the power to do this.'"

But it turned out that Boris had both the power and the will, and within 24 hours it was announced that Blair was to "resign", and shortly after that the Mayor's office began to refer to Boris having shown his teeth by firing New Labour's favourite copper.

Boris was, as Blair recalls, "steely" and determined but there was no shouting or rudeness, nor a farewell handshake.

"He was very anxious and as I left he ran to the door, and called: 'Please make sure someone escorts Sir Ian out.' He was very courteous."

One of the oddities about Blair is that for a man disliked by many Met colleagues for having been too political a Commissioner rather than a "copper's copper", he lacks basic political acumen and most of all, an early warning system of trouble ahead.

Almost everyone within a half-mile radius of City Hall knew last autumn that the new Mayor badly needed a grand political gesture to show that he was belatedly taking charge of the London machinery he had inherited from Ken Livingstone.

Yet Blair downplays any suggestion that he was sacked for being too close to New Labour and suggests that he was more a victim of Boris's vanity and insecurity.

He likens his sacking to the way Mayor Rudy Giuliani disposed of his popular police chief Bill Bratton when the latter became too prominent.

"Boris didn't want somebody who by that stage was as large a figure in the public mind as he was," he says, somewhat unrealistically and immodestly.

Blair acknowledges he was initially slow to appreciate the scale of the catastrophe that was ultimately to define his tenure heading the Met: the shooting of Jean Charles de Menezes in July 2005.

"One thing is important to get over," he says during an interview in the Paddington Hilton to promote his sometimes tediously exculpatory memoir Policing Controversy, "the shooting of somebody at that moment was not our main problem. It was a bad problem, but it wasn't anything like the main problem, which was looking for something that had never ever been dreamt of, which was suicide bombers on the run."

On the face of it, that is a perfectly reasonable assertion. It is easy to forget now that on July 22nd 2005, hundreds of thousands of Londoners were too scared to get on a tube or bus after the 7/7 attacks.

Yet in the book, and indeed in speaking about the shooting in person, he is strangely bloodless. Perhaps it has something to do with his easy resort to the jargon of New Labour.

For instance, while conceding errors in handling the row about de Menezes's death, he says he and his commanders were busy "taking every step to reach out to communities about what was going on".

There may be legal constraints but surely it is slightly shocking that more than four years after the event, Blair has still not personally written to the de Menezes family to express remorse.

And he still has a tin ear in talking about the fiasco, stating things that might be true, but are still unhelpful, such as: "I had every confidence in the team that had carried out the operation. Cressida Dick and her team, they were the absolute A-Team in the Met."

Blair concedes to missing being at the centre of action in the capital, and now lectures in Britain and abroad about policing.

He is clearly chuffed to have been elected an "honorary student" (or fellow) at his old Oxford college, Christ Church, which confers tempting privileges, including full dining rights. His hair has gone rather grey but he looks much more relaxed these days in a casual grey shirt. He reads a great deal, mostly history.

His time at the Met ended in bathetic chaos, with publicly aired acrimony between the top commanders such as Brian Paddick and anti-terrorism chief Andy Hayman all blaming each other for botching the aftermath of the de Menezes shooting.

Blair still seems baffled that he was not told when it was clear they had shot an innocent man, though he though he is still reluctant to acknowledge how this must surely have reflected on his leadership and popularity.

"I should have been told, and I find it very difficult that I wasn't and that's not just by Andy, but by others as well. A number of people made a bad call."

He has not spoken to Hayman or Paddick - both of whom he regarded as close friends during his long police career, and have since written memoirs unflattering of their former boss - since he left. Hayman will not return his calls.

However, Blair professes full confidence in his successor, Sir Paul Stephenson, and in his chances of keeping Londoners safe during the Olympics.

The problem, Blair suggests, will be that the Home Office will become obsessively risk averse while the mayor will, on behalf of Londoners, have to stop the capital becoming an armed fortress.

"It will be the first games to be held in a liberal democracy since the advent of 9/11. There was no chance of an attack on the Beijing games for obvious reasons," he says, adding that the whole of the UK, not just London, will be a potential terrorist target in 2012.

"The second biggest sporting event is the World Cup soccer, which is 32 nations playing one game. This is 150 nations playing 100 games, so it's a very different thing."

Blair can be touchy about any suggestion that he was the author of his own downfall for becoming too close to the Government and Ken Livingstone. "No one knows what my politics are," he tells me. "While in office I was very critical to their faces of some New Labour approaches."

I suggest that in his book, he seems like a clear supporter of the government, generally writing about Conservatives, and the press - particularly the Daily Mail - as enemy forces. He is specifically opposed to the Conservative plans for elected police chiefs.

"No," he insists when I tell him I think I have guessed what his politics are, "you wouldn't know." Rather, he argues that Conservatives made themselves his opponents because "they decided from quite early on that they didn't like the cut of my jib, and they were very rude".

He says that no one has suggested to him that he might take a seat in the House of Lords but that if he did go to the Upper House, he would only go as a cross-bencher.

Blair has some interesting ideas about policing, beyond his now rather dated notions of "reaching out" to communities and minorities (his credibility on the latter was undermined by race discrimination suits launched against him by senior non-white officers).

He was unusual as a commissioner in not issuing blanket demands for "more resources", and indeed he believes there are probably too many warranted officers in London.

He would rather cut those numbers and pay civilians to do more work for the police officers. "The detective is virtually doing the photocopying," he says.

"Officers are constantly doing paperwork that could easily be done by someone who is not warranted. You very rarely see police officers not working. The problem is that they are often are working on things they don't need all their training to do."

To achieve these reforms, there would need to be a new Royal Commission, he believes, because any fundamental change in policing is so politically fraught.

"There's not a particular consensus any more about the police should do, and some of the issues are wrapped up in a piece of political machismo about officer numbers. The gravest problem is that politicians of all sides have constantly engaged in a Dutch auction of how many officers they can supply.

"I'm clear the police will soon price themselves out of the market because it is a very expensive thing to have police officers doing jobs that don't need police officers to do them."

Blair also blames his namesake, Tony, for what he regards as an exaggerated concern about his involvement in lobbying MPs to extend detention without charge to 90 days.

This, he says, should have led to a perfectly sensible political deal but he had not reckoned on Downing Street turning it into a specifically political issue.

"I thought a very reasonable compromise was going to turn up, and so did Charles Clarke, [then Home Secretary] and then Tony Blair stamped his standard on 90 days. Then the politics came in, it didn't start off as political but it became political, and once you're already in it, you can't actually then say: 'Now it's political I'm not going to say anything.'"

If there is an irony underlying Sir Ian Blair's four years as Britain's top copper, it is that this most political of police officers was ultimately undone by dirty politics.

Blair does not wish to seem resentful of the way his tenure ended, but one senses a deep layer of bitterness. He cannot resist contrasting the new mayor's performance with Ken's.

"Ken is a master of detail," he says, making clear his successor is not.

And of Boris? "I am surprised how little I have seen of him as a man. I've seen lots of photographs of him but I haven't got the same sense of things being driven by him as I did with Ken. You could feel that Ken was running London in a much more direct way than I am seeing with Boris."

Then, lest there be any misunderstanding, Blair sets the record straight once more.

"Let me make it absolutely clear, he's a very likeable man. Even now I don't have any personal resentment, I don't see it in those terms."